1. Field of Invention
The present invention relates to an insulating-film trapping type non-volatile semiconductor storage device (hereinafter “MONOS”) and a manufacturing method thereof.
2. Description of Related Art
As a semiconductor storage device capable of electrically writing and erasing, there has been a non-volatile semiconductor storage device, which can retain stored date even when power for a memory is eliminated. As such a semiconductor storage device, there is a MONOS type semiconductor storage device.
A MONOS type semiconductor storage device 1000 according to a related art example is shown in FIG. 9. In the semiconductor storage device 1000, a gate electrode 130 is formed above a semiconductor substrate 110 with an ONO film 120 therebetween. A thermal oxide film 132 is formed on a side surface of the gate electrode 130, and a surface of the semiconductor substrate 110 where a side wall insulating layer 140 is formed. In the semiconductor substrate 110, impurity layers 150 and 152 having an LDD structure are formed at the side of the gate electrode 130.